I like to use my smartphone with all functions always activated, but this is naturally a thing which contributes negatively to battery life. I tried to switch off, for example, the Bluetooth when I'm not using it, but then I get back to my car and only when I'm receiving a phone call I discover I'm not linked with the car because I dismembered to reactivate the Bluetooth function... So, no... I cannot use a device in this way. Recently I discover a little (but powerful) application which helps me doing this automatically: NFC Task Launcher. Yes, the name means you should use it with NFC tags, but developers also add other interesting features even without NFC: wifi connect/disconnect, bluetooth connect/disconnect, gps position, ... To show you how my smartphone usage has changed, I just describe some tasks I added to this application.
- Event: Connection to Home WiFi. Actions: disable GPS, disable 3G data, disable bluetooth
- Event: Disconnecting from Home Wifi. Actions: Enable GPS, Enable 3G Data, Enable bluetooth
- Event: Connection to Car Bluetooth system (done automatically after wifi disconnection event) Actions: Disable WiFi, Switch to Driving Mode
- Event: Disconnection from Bluetooth car system Action: Enable WiFi, Switch off Driving mode
UPDATE: After the post comment (you can read) about a different app to do something similar, I investigated a little bit and I found a better application (with more triggers and events available), in my opinion, easy to use and with a cool web interface: https://play.google.com/store/apps/details?id=com.arlosoft.macrodroid